Okay, so I've decided to do some more work on that Univega I posted about the other day. I will not be putting my 105 group on it, but I would like to do some work to her. I plan on putting new brake levers on(found some decent looking Tektro levers on Ebay for $20). I would also like to upgrade the derailleurs as the current setup is very finicky. I've seen some neat old groups on Ebay, here is an example:

What do y'all think? This will be my first real attempt at doing any work on a bike and I have an experienced friend guiding me. I also ordered a few books on maint. so that will be a help.
As far as figuring out what is on the bike now, I cannot find serial numbers or anything, all the parts say is Shimano. Any advice? I think it's a 10 speed but I'm not sure....

Thanks!!